You live in Karachi so you could convince your father that there is no spare parts issue here. There are many authorized dealers as well as well reputed showrooms.
GD-110 is a quality bike and I don't think you would need any spare part (atleast from engine side) any time before 5years. Yes gadgets like speedometer, headlight, mudguards..etc wont be easily available but I have done a little survey that such parts of GD-110 can be ordered and their delivery within 3 working days.
Bro, you have missed the chance. I am not sure about the power but surely you will miss the smoothness, quite and vibration less ride of Junoon.